A067866 Numbers n such that n and 2^n end with the same three digits.
736, 1736, 2736, 3736, 4736, 5736, 6736, 7736, 8736, 9736, 10736, 11736, 12736, 13736, 14736, 15736, 16736, 17736, 18736, 19736, 20736, 21736, 22736, 23736, 24736, 25736, 26736, 27736, 28736, 29736, 30736, 31736, 32736, 33736, 34736
Offset: 1
Links
- Tanya Khovanova, Recursive Sequences
- Index entries for linear recurrences with constant coefficients, signature (2,-1).
Programs
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PARI
isok(n) = (2^n - n) % 1000 == 0; \\ Michel Marcus, Nov 23 2013
Formula
a(n) = 736 + 1000(n-1).
a(n) = 2*a(n-1)-a(n-2). G.f.: 8*x*(92+33*x)/(1-x)^2. [Colin Barker, Dec 01 2012]